9/12/2017: Heat returning to Texas

Main surface feature of interest this morning in the region is the remnant low of Hurricane Irma now positioned over the Tennessee Valley. Some high clouds from Irma are actually spreading over Northeast Texas this morning, but besides these high clouds, Irma will not bring much in terms of sensible impacts to Texas. Otherwise, surface observations show another mild morning with 60s across interior Texas, and 70s along the Gulf Coast. At the upper-levels, this morning’s 500 mb analysis shows that a ridge is beginning to build in across the Southwest. This ridge is forecast to continue building east over the next several days, bringing a return to hot weather.

Taking a look at the hemispheric chart, the wave count appears to be 4-5, which should keep us in a fairly stagnant longwave pattern for the next several days. A subtle Rex block also appears to be in place across the eastern to central Pacific Ocean. Furthermore, both the GFS and European ensembles keep warm anomalies across the interior United States through the duration of their forecasts. There’s a small hint at a brief breakdown from positive to neutral anomalies around Sunday, but I don’t see much in the way of a synoptic-scale feature that would drive this in the deterministic forecasts, and even if it is borne out, it would likely be brief, and the multi-day average will certainly remain above normal. Bottom line is that it looks like we will begin to warm up through late week, and stay warm for several days.

This idea is reflected in the Climate Prediction Center (CPC) forecasts which show a >60% chance of above normal temperatures through next week for most of Texas, with a >50% chance of above normal temperatures for September 19-25 (around the Fall Equinox). Beyond the equinox, the latest CPC forecast shows equal chances across Texas towards the end of September and into early October.